Surgical instrument with switch activation control

ABSTRACT

A surgical instrument includes a housing and an elongated shaft operably coupled to an actuating mechanism moveable between an actuated position and an unactuated position. An end effector includes a pair of opposing first and second jaw members and is adapted to connect to a source of electrosurgical energy. A switch is moveable between an activated position to initiate delivery of electrosurgical energy to the end effector and a deactivated position to terminate delivery of electrosurgical energy to the end effector. A switch activation member is configured to move the switch between an activated position and a deactivated position. A switch control member is configured to maintain the switch in the activated position during at least partial movement of the actuating mechanism from the actuated position to the unactuated position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patent application Ser. No. 14/105,374 filed on Dec. 13, 2013, now U.S. Pat. No. 9,456,863 which claims priority to U.S. Provisional Patent Application No. 61/776,185 filed on Mar. 11, 2013, the entire contents of each of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

The present disclosure relates generally to the field of surgical instruments. In particular, the present disclosure relates to an endoscopic electrosurgical forceps that includes a system and method for controlling the activation and deactivation of treatment energy.

2. Background of Related Art

Instruments such as electrosurgical forceps are commonly used in open and endoscopic surgical procedures to coagulate, cauterize and seal tissue. Such forceps typically include a pair of jaws that can be controlled by a surgeon to grasp targeted tissue, such as, e.g., a blood vessel. The jaws may be approximated to apply a mechanical clamping force to the tissue, and are associated with at least one electrode to permit the delivery of electrosurgical energy to the tissue. The combination of the mechanical clamping force and the electrosurgical energy has been demonstrated to join adjacent layers of tissue captured between the jaws. When the adjacent layers of tissue include the walls of a blood vessel, sealing the tissue may result in hemostasis, which may facilitate the transection of the sealed tissue. A detailed discussion of the use of an electrosurgical forceps may be found in U.S. Pat. No. 7,255,697 to Dycus et al.

A bipolar electrosurgical forceps typically includes opposed electrodes disposed on clamping faces of the jaws. The electrodes are charged to opposite electrical potentials such that an electrosurgical current may be selectively transferred through tissue grasped between the electrodes. To effect a proper seal, particularly in relatively large vessels, two predominant mechanical parameters must be accurately controlled; the pressure applied to the vessel, and the gap distance established between the electrodes.

Both the pressure and gap distance influence the effectiveness of the resultant tissue seal. If an adequate gap distance is not maintained, there is a possibility that the opposed electrodes will contact one another, which may cause a short circuit and prevent energy from being transferred through the tissue. Also, if too low a force is applied the tissue may have a tendency to move before an adequate seal can be generated. The thickness of a typical effective tissue seal is optimally between about 0.001 and about 0.006 inches. Below this range, the seal may shred or tear and above this range the vessel walls may not be effectively joined. Closure pressures for sealing large tissue structures preferably fall within the range of about 3 kg/cm² to about 16 kg/cm².

SUMMARY

The present disclosure relates generally to the field of surgical instruments. In particular, the present disclosure relates to an endoscopic electrosurgical forceps that includes a system and method for controlling the activation and deactivation of treatment energy.

As is traditional, the term “distal” refers herein to an end of the apparatus that is farther from an operator, and the term “proximal” refers herein to the end of the electrosurgical forceps that is closer to the operator.

According to one aspect of the present disclosure, a surgical instrument is provided. The surgical instrument includes a housing and an elongated shaft. The elongated shaft has a distal portion extending from the housing and a proximal portion coupled to the housing. A longitudinal axis is defined through the elongated shaft. An actuating mechanism is operably coupled to the elongated shaft and is moveable relative to the housing between an actuated position and an unactuated position to selectively move the elongated shaft along the longitudinal axis. An end effector includes a pair of opposing first and second jaw members movable relative to each other from a first position wherein the jaw members are disposed in spaced relation relative to one another to a second position wherein the jaw members cooperate to grasp tissue. The end effector is adapted to connect to a source of electrosurgical energy for conducting electrosurgical energy through tissue grasped between the jaw members to effect a tissue seal. A switch is supported by the housing and moveable between an activated position to initiate delivery of electrosurgical energy from the electrosurgical energy source to the end effector and a deactivated position to terminate delivery of electrosurgical energy from the electrosurgical energy source to the end effector. A switch activation member is disposed on the actuating mechanism and is configured to move the switch to the activated position upon movement of the actuating mechanism to the actuated position and to the deactivated position upon movement of the actuating mechanism to the unactuated position. A switch control member is configured to maintain the switch in the activated position during at least partial movement of the actuating mechanism from the actuated position to the unactuated position.

Additionally or alternatively, the surgical instrument may also include a knife blade supported in the elongated shaft and moveable in a longitudinal direction through a knife channel defined along a length of at least one of the jaw members to cut tissue disposed between the jaw members.

Additionally or alternatively, the switch may be operably coupled to a depressible button extending from the housing and configured to be selectively engaged by the switch activation member upon movement of the actuating mechanism to the actuated position.

Additionally or alternatively, the switch control member may include a biasing member disposed between the depressible button and the switch. The biasing member may be configured to maintain a force on the switch to maintain the switch in the activated position during at least partial movement of the actuating mechanism from the actuated position to the unactuated position.

Additionally or alternatively, the switch control member may include a biasing member extending from the actuating mechanism and having a button activation post configured to engage the depressible button. The biasing member may be configured to maintain a force on the switch to maintain the switch in the activated position during at least partial movement of the actuating mechanism from the actuated position to the unactuated position.

Additionally or alternatively, the switch control member may include a biasing member disposed between the depressible button and the switch. The depressible button may have a switch activation post extending therefrom at least partially through the biasing member. The biasing member may be configured to maintain a force on the switch to maintain the switch in the activated position during at least partial movement of the actuating mechanism from the actuated position to the unactuated position.

Additionally or alternatively, the switch control member may include a biasing member extending from the actuating mechanism configured to maintain a force on the switch to maintain the switch in the activated position during at least partial movement of the actuating mechanism from the actuated position to the unactuated position.

Additionally or alternatively, the second jaw member may be mechanically coupled to a distal end of the elongated shaft and the first jaw member may be configured to move relative to the second jaw member.

Additionally or alternatively, the switch control member may include a leaf spring.

Additionally or alternatively, the switch control member may include a coiled spring.

Additionally or alternatively, the surgical instrument may also include a stationary actuation member axially disposed within the elongated shaft. The stationary actuation member may include a cam pin mechanically coupled to the distal portion of the elongated shaft. One or both of the first and second jaw members may include a camming slot configured to engage the cam pin to move the at least one movable jaw member about a pivot between the first position and the second position upon movement of the elongated shaft along the longitudinal axis.

Additionally or alternatively, an electrical insulator may be coupled to one or both of the jaw members.

Additionally or alternatively, the surgical instrument may also include an electrically conductive tissue sealing surface extending along a length of at least one jaw member and adapted to connect to the source of electrosurgical energy.

According to another aspect of the present disclosure, a surgical instrument is provided. The surgical instrument includes a housing and an elongated shaft. The elongated shaft has a distal portion extending from the housing and a proximal portion coupled to the housing. A longitudinal axis is defined through the elongated shaft. An actuating mechanism is operably coupled to the elongated shaft and is moveable relative to the housing between an actuated position and an unactuated position to selectively move the elongated shaft along the longitudinal axis. An end effector includes a pair of opposing first and second jaw members movable relative to each other from a first position wherein the jaw members are disposed in spaced relation relative to one another to a second position wherein the jaw members cooperate to grasp tissue. The end effector is adapted to connect to a source of electrosurgical energy for conducting electrosurgical energy through tissue grasped between the jaw members to effect a tissue seal. A switch is supported by the housing and moveable between an activated position to initiate delivery of electrosurgical energy from the electrosurgical energy source to the end effector and a deactivated position to terminate delivery of electrosurgical energy from the electrosurgical energy source to the end effector. A switch activation member is disposed on the actuating mechanism and is configured to move the switch to the activated position upon movement of the actuating mechanism to the actuated position and to the deactivated position upon movement of the actuating mechanism to the unactuated position. A switch control member is configured to maintain the switch in the activated position during at least partial movement of the actuating mechanism from the actuated position to the unactuated position. A knife blade is supported in the elongated shaft and is moveable in a longitudinal direction through a knife channel defined along a length of at least one of the jaw members to cut tissue disposed between the jaw members.

Additionally or alternatively, the switch may be operably coupled to a depressible button extending from the housing and configured to be selectively engaged by the switch activation member upon movement of the actuating mechanism to the actuated position.

Additionally or alternatively, the switch control member may be disposed between the depressible button and the switch.

Additionally or alternatively, the switch control member may be disposed on the actuating mechanism.

According to another aspect of the present disclosure, a switch actuation control mechanism for an electrosurgical instrument having a housing and an end effector adapted to connect to a source of electrosurgical energy for conducting electrosurgical energy through tissue grasped by the end effector to effect a tissue seal is provided. The switch actuation control mechanism including a switch supported by the housing. The switch is moveable between an activated position to initiate delivery of electrosurgical energy from the electrosurgical generator to the end effector and a deactivated position to terminate delivery of electrosurgical energy from the electrosurgical generator to the end effector. A switch activation member is moveable between an actuated position and an unactuated position to selectively move the switch between the activated position and the deactivated position. A switch control member is configured to maintain the switch in the activated position during at least partial movement of the switch activation member from the actuated position to the unactuated position.

Additionally or alternatively, the switch control member may be disposed between the switch and the switch activation member.

Additionally or alternatively, the switch control member may include a biasing member configured to maintain a force on the switch to maintain the switch in the activated position during at least partial movement of the switch activation member from the actuated position to the unactuated position.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the detailed description of the embodiments given below, serve to explain the principles of the disclosure.

FIG. 1 is a perspective view of an electrosurgical forceps according to an embodiment of the present disclosure including a housing, an elongated shaft, and an end effector;

FIG. 2A is an enlarged, perspective view of the end effector of FIG. 1 depicted with a pair of jaw members in an open configuration;

FIG. 2B is an enlarged, perspective view of the end effector of FIG. 1 depicted with the pair of jaw members in a closed configuration;

FIG. 3A is a perspective view of the end effector and elongated shaft of FIG. 1 with parts separated;

FIG. 3B is cross-sectional view taken along line 3B-3B of FIG. 3A showing a distal portion of the electrosurgical forceps of FIG. 1 depicting a tube guide;

FIG. 4 is a proximally-facing, perspective view of a rotation knob depicting a passageway for receiving the elongated shaft of FIG. 1;

FIG. 5 is a cross-sectional, perspective view of the end effector of FIG. 1;

FIG. 6 is a partial, proximal-facing perspective view of a distal portion of a jaw actuation mechanism of the end effector of FIG. 1;

FIG. 7 is a partial, distal-facing perspective view of distal portion of a knife actuation mechanism of the end effector of FIG. 1;

FIG. 8 is a top, perspective view of a lower jaw member of the end effector of FIG. 1;

FIG. 9 is a top, cross-sectional, perspective view of the lower jaw member of FIG. 8;

FIG. 10 is a perspective view of a proximal portion of the instrument of FIG. 1 with a portion of the housing removed revealing internal components;

FIG. 11 is a partial, side view of a proximal portion of the instrument of FIG. 1;

FIG. 12A is an enlarged, perspective view of a proximal portion of the knife actuation mechanism of the end effector of FIG. 1;

FIG. 12B is an enlarged, cross-sectional, side view of a knife collar of the knife actuation mechanism of the end effector of FIG. 1;

FIG. 13A is an internal, side view of the proximal portion of the instrument of FIG. 10 depicting a movable handle in a separated position with respect to a stationary handle, which corresponds to the open configuration of the end effector depicted in FIG. 2A, and a knife trigger in a separated configuration with respect to the stationary handle, which corresponds to an un-actuated or proximal configuration of a knife with respect to the jaw members;

FIG. 13B is an internal, side view of the proximal portion of the instrument of FIG. 10 depicting the movable handle in an intermediate position with respect to the stationary handle, which corresponds to a first closed configuration of the end effector wherein the jaw members encounter one another;

FIG. 13C is an internal, side view of the proximal portion of the instrument of FIG. 10 depicting the movable handle in an approximated configuration with respect to the stationary handle, which corresponds to a second closed configuration of the end effector wherein the jaw members apply an appropriate pressure to generate a tissue seal; and

FIG. 13D is an internal, side view of the proximal portion of the instrument of FIG. 10 depicting the knife trigger in an actuated configuration, which corresponds to an actuated or distal position of the knife with respect to the jaw members.

DETAILED DESCRIPTION

Referring initially to FIG. 1, an embodiment of an electrosurgical forceps 100 generally includes a housing 112 that supports various actuators thereon for remotely controlling an end effector 114 through an elongated shaft 116. Although this configuration is typically associated with instruments for use in laparoscopic or endoscopic surgical procedures, various aspects of the present disclosure may be practiced with traditional open instruments and in connection with certain endoluminal procedures.

The housing 112 is constructed of a left housing half 112 a and a right housing half 112 b. The left and right designation of the housing halves 112 a, 112 b refer to the respective directions as perceived by an operator using the forceps 100. The housing halves 112 a, 112 b are constructed of sturdy plastic, and are joined to one another by adhesives, ultrasonic welding or other suitable assembly methods.

To mechanically control the end effector 114, the housing 112 supports a stationary handle 120, a movable handle 122, a trigger 126 and a rotation knob 128. The movable handle 122 is operable to move the end effector 114 between an open configuration (FIG. 2A) wherein a pair of opposed jaw members 130, 132 are disposed in spaced relation relative to one another, and a closed or clamping configuration (FIG. 2B) wherein the jaw members 130, 132 are closer together. Approximation of the movable handle 122 with the stationary handle 120 serves to move the end effector 114 to the closed configuration and separation of the movable handle 122 from the stationary handle 120 serves to move the end effector 114 to the open configuration. The trigger 126 is operable to extend and retract a knife blade 156 (see FIGS. 2A and 2B) through the end effector 114 when the end effector 114 is in the closed configuration. The rotation knob 128 serves to rotate the elongated shaft 116 and the end effector 114 about a longitudinal axis A-A extending through the forceps.

To electrically control the end effector 114, the stationary handle 120 supports a depressible button 137 thereon, which is operable by the user to initiate and terminate the delivery of electrosurgical energy to the end effector 114. More specifically, and as illustrated in FIGS. 13A-13D, the depressible button 137 is mechanically coupled to a switch 136 disposed within the stationary handle 120. In some embodiments, the button 137 is engageable by a button activation post 138 extending from a proximal side of the moveable handle 122 upon proximal movement of the moveable handle 122. The switch 136 is in electrical communication with a source of electrosurgical energy such as electrosurgical generator 141 or a battery (not shown) supported within the housing 112. The generator 141 may include devices such as the LIGASURE® Vessel Sealing Generator and the Force Triad® Generator sold by Covidien Energy-based Devices of Boulder, Colo. A cable 143 extends between the housing 112 and the generator 141 and includes a connector (not shown) thereon such that the forceps 100 may be selectively coupled and decoupled electrically from the generator 141.

As further detailed hereinbelow, a user squeezes moveable handle 122 to approximate the moveable handle 122 with the stationary handle 120 and activate the switch 136 to initiate the delivery of electrosurgical energy to the end effector 114 and effect a tissue seal. Upon completion of a tissue seal, the user operates the trigger 126 to advance the knife blade 156 through the end effector 114 when the end effector 114 is in the closed configuration. As the user reaches for the trigger 126 with the same hand that is squeezing the moveable handle 122 to keep the end effector 114 in the closed configuration, the moveable handle 122 may inadvertently move distally away from the stationary handle 120. This distal movement of the moveable handle 122 may cause the button activation post 138 to disengage the button 137 and, in turn, the button 137 disengages and deactivates the switch 136 to terminate delivery of electrosurgical energy to the end effector 114. When the user moves the trigger 126 proximally to advance the knife blade 156 through the end effector 114, the user re-squeezes the moveable handle 122 such that button activation post 138 reengages and depresses the button 137, thereby reactivating the switch 136. Reactivation of the switch 136 reinitiates the delivery of electrosurgical energy to the end effector 114 while the knife blade 156 is advanced through the end effector 114.

In some embodiments, the forceps 100 may include an enhanced switch control feature configured to prevent the deactivation and reactivation of the switch 136 to terminate and reinitiate, respectively, the delivery of electrosurgical energy to the end effector 114 during operation of the trigger 126. With reference to FIG. 10, one such embodiment is depicted, wherein the button 137 includes a switch activation post 137 a extending therefrom and a biasing member 136 a (e.g., a coiled spring) disposed about the switch activation post 137 a between the switch 136 and the button 137. Switch activation post 137 a is positioned relative to the switch 136 such that when button activation post 138 engages and depresses button 137 upon approximation of moveable handle 122 with stationary handle 120, switch activation post 137 a engages and activates switch 136. Depression of button 137 also causes biasing member 136 a to compress between the button 137 and the switch 136 and to apply a spring force on switch 136. If the moveable handle 122 inadvertently moves distally away from the stationary handle 120 during operation of the trigger 126, the biasing member 136 a, although now slightly decompressed, serves to mitigate the effects of this distal movement of the moveable handle 122 by maintaining a spring force on the switch 136. This spring force maintained on the switch 136 is sufficient to keep the switch 136 activated during at least a portion of travel of the moveable handle 122 in the distal direction, such that the switch 136 is not deactivated and reactivated during operation of the trigger 126. As the moveable handle 122 moves farther away from the stationary handle 120 to move the end effector 114 to the open configuration (FIG. 2A), the spring force maintained on the switch 136 by the biasing member 136 a relents and, as a result, the switch 136 is deactivated.

Referring now to FIGS. 2A-3, the end effector 114 may be moved from the open configuration (FIG. 2A) wherein tissue (not shown) is received between the jaw members 130, 132, and the closed configuration (FIG. 2B), wherein the tissue is clamped and treated. The upper and lower jaw members 130, 132 are electrically coupled to cable 143, and thus to the generator 141 (e.g., via a respective wire extending through the elongated shaft 116) to provide an electrical pathway to a pair of electrically conductive, tissue-engaging sealing plates 148, 150 disposed on the lower and upper jaw members 132, 130, respectively. The sealing plate 148 of the lower jaw member 132 opposes the sealing plate 150 of the upper jaw member 130, and, in some embodiments, the sealing plates 148 and 150 are electrically coupled to opposite terminals, e.g., positive or active (+) and negative or return (−) terminals associated with the generator 141. Thus, bipolar energy may be provided through the sealing plates 148 and 150. Alternatively, the sealing plates 148 and 150 and/or the end effector 114 may be configured for delivering monopolar energy to the tissue. In a monopolar configuration, one or both sealing plates 148 and 150 deliver electrosurgical energy from an active terminal, e.g. (+), while a return pad (not shown) is placed generally on a patient and provides a return path to the opposite terminal, e.g. (−), of the generator 141. Each jaw member 130, 132 includes a jaw insert 140 and an insulator 142 that serves to electrically insulate the sealing plates 150, 148 from the jaw insert 140 of jaw members 130, 132, respectively.

Referring to FIG. 3, the elongated shaft 116 includes various longitudinal components that operatively couple the end effector 114 to the various actuators supported by the housing 112 (FIG. 1). An outer shaft member 160 defines an exterior surface of the elongated shaft 116 and supports movement of other components therethrough as described below. The outer shaft member 160 is configured for longitudinal motion with respect to an inner actuation member 180 axially received within the outer shaft member 160. The inner actuation member 180 may be a rod, shaft, stamped metal, or other suitable mechanical component. A proximal portion 166 of the outer shaft member 160 is configured for receipt within the housing 112 (FIG. 1), and includes features for operatively coupling the outer shaft member 160 to the actuators supported thereon, e.g. the movable handle 122. A distal portion 186 of the inner actuation member 180 includes a longitudinal recess 190 defined therein that provides clearance for the pivot pin 144 and thus, permits longitudinal reciprocation of the pivot pin 144 (via longitudinal reciprocation of the outer shaft member 160) independent of the inner actuation member 180. Distally of the longitudinal recess 190, the cam pin 192 is mechanically coupled (e.g., via welding, friction-fit, laser welding, etc.) to the distal portion 186 of the inner actuation member 180. A proximal portion 188 of the inner actuation member 180 includes a washer 187 coupled thereto (FIG. 10). The washer 187 is supported within the housing 112 and serves to prohibit longitudinal motion of the inner actuation member 180 parallel to the longitudinal axis A-A.

The jaw members 130, 132 may be pivoted about the pivot pin 144 to move the end effector 114 to the closed configuration of FIG. 2B wherein the sealing plates 148, 150 provide a pressure to tissue grasped therebetween. In some embodiments, to provide an effective seal, a pressure within a range between about 3 kg/cm² to about 16 kg/cm² and, desirably, within a working range of 7 kg/cm² to 13 kg/cm² is applied to the tissue. Also, in the closed configuration, a separation or gap distance “G” may be maintained between the sealing plates 148, 150 by an array of stop members 154 (FIG. 2A) disposed on or adjacent the sealing plates 148, 150. The stop members 154 contact opposing surfaces on the opposing jaw member 130, 132 and prohibit further approximation of the sealing plates 148, 150. In some embodiments, to provide an effective tissue seal, an appropriate gap distance of about 0.001 inches to about 0.010 inches and, desirably, between about 0.002 and about 0.005 inches may be provided. In some embodiments, the stop members 154 are constructed of an electrically non-conductive plastic or other material molded onto the jaw members 130, 132, e.g., by a process such as overmolding or injection molding. In other embodiments, the stop members 154 are constructed of a heat-resistant ceramic deposited onto the jaw members 130, 132.

Electrosurgical energy may be delivered to the tissue through the electrically conductive seal plates 148, 150 to effect a tissue seal. Once a tissue seal is established, a knife blade 156 having a sharp distal cutting edge 157 may be advanced through a knife channel 158 defined in one or both jaw members 130, 132 to transect the sealed tissue. Knife blade 156 is depicted in FIG. 2A as extending from the elongated shaft 116 when the end effector 114 is in an open configuration. In some embodiments, a knife lockout is provided to prevent extension of the knife blade 156 into the knife channel 158 when the end effector 114 is in the open configuration.

The proximal portion 166 of the outer shaft member 160 includes various features that serve to couple the outer shaft member 160 to various elements of the housing 112. More specifically, the proximal portion 166 of the outer shaft member 160 includes, in order from distal to proximal, a longitudinal slot 169 extending distally from a proximal end thereof to couple the outer shaft member 160 to the rotation knob 128, a longitudinal knife slot 168 defined therethrough, a pair of opposing distal locking slots 161 a, 161 b, and a pair of opposing proximal locking slots 171 a, 171 b. The connection established between the outer shaft member 160 and the rotation knob 128 is described below with reference to FIG. 4.

The pivot pin 144 extends through a proximal portion of each of the jaw members 130, 132 to pivotally support the jaw members 130, 132 at the distal end of the outer shaft member 160. With reference to FIG. 8, a proximal portion of each of the jaw members 130, 132 includes two laterally spaced parallel flanges or “flags” 130 a, 130 b and 132 a, 132 b respectively, extending proximally from a distal portion of the jaw members 130 and 132. A lateral cam slot 130 c and a lateral pivot bore 130 d extend through each of the flags 130 a, 130 b of the upper jaw member 130. Similarly, a lateral cam slot 132 c and a lateral pivot bore 132 d extend through each of the flags 132 a, 132 b of the lower jaw member 132. The pivot bores 130 d, 132 d receive the pivot pin 144 in a slip-fit relation that permits the jaw members 130, 132 to pivot about the pivot pin 144 to move the end effector 114 between the open and closed configurations (FIGS. 2A and 2B, respectively).

A knife rod 102 is coupled (e.g., via welding) at a distal-most end to the sharpened knife blade 156 and includes an angled proximal end 108 that provides a mechanism for operatively coupling the knife rod 102 to the trigger 126. The connection between the knife rod 102 and the trigger 126 is described in detail below with reference to FIGS. 10, 11, 12A, and 12B. The sharp edge 157 of the knife blade 156 may be applied to the distal end of the knife blade 156 subsequent to the stamping process that forms the profile. For example, various manufacturing techniques may be employed such as grinding, coining, electrochemical etching, electropolishing, or other suitable manufacturing processes, for forming sharpened edges.

Referring to FIGS. 3A and 3B, a tube guide 109 is disposed within the outer shaft member 160 and includes a guide lumen 107 axially disposed therethrough and a longitudinal guide recess 105 formed therein. The inner actuation member 180 is received within the guide lumen 107, which serves to orient and align the inner actuation member 180 within the outer shaft member 160. The knife rod 102 is received within the longitudinal recess 105, which serves to guide longitudinal motion of the knife rod 102 within the outer shaft member 160. In this way, the inner actuation member 180 and the knife rod 102 are aligned within the outer shaft member 160 by the tube guide 109 such that the knife rod 102 is free to move longitudinally relative to the inner actuation member 180.

Referring now to FIG. 4, the rotation knob 128 includes a passageway 129 defined therethrough for receiving the outer shaft member 160. The passageway 129 has a generally circular profile corresponding to the circular profile of the outer shaft member 160. The passageway 129 includes a longitudinal keying member 124 that is configured to align with and be seated within longitudinal slot 169 (FIG. 3A) of the outer shaft member 160. The keying member 124 projects laterally inward along the length of passageway 129 such that the insertion of the proximal end of the outer shaft member 160 into the passageway 129 of the rotation knob 128 operatively couples the outer shaft member 160 to the rotation knob 128. Rotational motion imparted to the rotation knob 128 may thus impart rotational motion to each of the components of the elongated shaft 116, and to the end effector 114, which is coupled thereto. As shown in FIG. 12, the rotation knob 128 is seated within an interior compartment 134 of the housing 112 and, as shown in FIG. 1, extends laterally outward from opposing sides of the housing 112 (only shown extending laterally outward from housing half 112 b).

Referring now to FIG. 5, the end effector 114 is coupled to the distal end of the inner actuation member 180 by the cam pin 192. The cam pin 192 represents a longitudinally stationary reference for the longitudinal movements of the outer shaft member 160, the pivot pin 144, and the knife rod 102. The cam pin 192 extends through the flags 132 a, 132 b of the lower jaw member 132 and the flags 130 a and 130 b of the upper jaw member 130.

Referring now to FIG. 6, the end effector 114 is shown in the open configuration. Since the inner actuation member 180 is coupled to the cam pin 192, when the outer shaft member 160 is in the distal position (unactuated) and the inner actuation member 180 is in the proximal position relative to the outer shaft member 160, the cam pin 192 is located in a proximal position in cam slots 130 c and 132 c defined through the flags 130 a, 130 b, 132 a, 132 b of the jaw members 130, 132, respectively.

The outer shaft member 160 may be drawn proximally relative to the inner actuation member 180 and the cam pin 192 to move the end effector 114 to the closed configuration (see FIG. 2B). Since the longitudinal position of the cam pin 192 is fixed, and since the cam slots 130 c, 132 c are obliquely arranged with respect to the longitudinal axis A-A, proximal retraction of the outer shaft member 160 induces distal translation of the cam pin 192 through the cam slots 130 c, 132 c and jaw member 130 to pivot toward jaw member 132 about the pivot pin 144. Conversely, when the end effector 114 is in the closed configuration, longitudinal translation of the outer shaft member 160 in a distal direction induces proximal translation of the cam pin 192 through the cam slots 130 c, 132 c and jaw member 130 to pivot away from jaw member 132 toward the open configuration.

Referring now to FIG. 7, the pins 144, 192 do not interfere with the reciprocal motion of the knife blade 156. A proximal portion of the insulator 142 forms a blade guide 142 a (also see FIGS. 8 and 9) that serves to align the knife blade 156 such that the knife blade 156 readily enters the knife channel 158 defined in the jaw members 130, 132 (jaw member 130 removed from view in FIG. 7 for clarity).

Referring now to FIGS. 8 and 9, the lower jaw member 132 is constructed of three major components. These components include the jaw insert 140, the insulator 142, and the sealing plate 148. The flags 132 a, 132 b of the jaw member 132 define a proximal portion of the jaw insert 140 and a generally u-shaped profile of the jaw insert 140 extends distally to support the tissue engaging portion of the jaw member 132. Upper jaw member 130 includes the same three major components as lower jaw member 132, including sealing plate 150, and is constructed in the same manner as lower jaw member 132.

The insulator 142 may be constructed of an electrically insulative plastic such as a polyphthalamide (PPA) (e.g., Amodel®), polycarbonate (PC), acrylonitrile butadiene styrene (ABS), a blend of PC and ABS, nylon, ceramic, etc. The electrically insulative plastic may be overmolded onto the jaw insert 140 in a single-shot injection molding process such that sealing plate 148 is overmolded to the jaw insert 140. Additionally or alternatively, the electrically insulative plastic may be mechanically coupled to the jaw insert 140, e.g., pressed, snapped, glued, etc. Various features may be molded into the insulator 142 that facilitate the attachment of the sealing plate 148 to the insert 140. For example, tabs may be provided that permit a snap-fit attachment of the sealing plate 148, or ridges may formed that permit ultrasonic welding of the sealing plate 148 onto the insulator 142. The sealing plate 148 may be constructed of an electrically conductive metal, and may be stamped from a flat sheet stock.

Referring now to FIG. 10, the connection of the movable handle 122 and the knife trigger 126 to the longitudinally movable components of the elongated shaft 116 is described. The movable handle 122 may be manipulated to impart longitudinal motion to the outer shaft member 160, and the knife trigger 126 may be manipulated to impart longitudinal motion to the knife rod 102. As discussed above, longitudinal motion of the outer shaft member 160 serves to move the end effector 114 between the open configuration of FIG. 2A and the closed configuration of FIG. 2B, and longitudinal motion of the knife rod 102 serves to move knife blade 156 through knife channel 158 (FIG. 2A).

The movable handle 122 is operatively coupled to the outer shaft member 160 by clevis 178 defined at an upper end of the movable handle 122. The clevis 178 is pivotally supported on the left housing half 112 b by a pivot boss 179. A second complementary pivot boss (not shown) is provided on the right housing half 112 a to support the clevis 178. The clevis 178 extends upwardly about opposing sides of a drive collar 184 (FIG. 11) supported on the outer shaft member 160 and includes rounded drive surfaces 197 a and 197 b thereon. Drive surface 197 a engages a proximal-facing surface of a distal spring washer 184 a and drive surface 197 b engages a distal facing surface of a proximal rim 184 b of the drive collar 184 (FIG. 11). The distal spring washer 184 a engages a proximal facing surface of a distal spring stop 184 c that, in turn, engages the opposing distal locking slots 161 a, 161 b (FIG. 3A) extending through the proximal portion 166 (FIG. 3A) of the outer shaft member 160 to couple the distal spring stop 184 c to the outer shaft member 160. The drive surfaces 197 a, 197 b are arranged along the longitudinal axis A-A such that pivotal motion of the movable handle 122 induces corresponding longitudinal motion of the drive collar 184 (FIG. 11) along the longitudinal axis A-A.

Referring now to FIG. 11, proximal longitudinal motion may be imparted to the outer shaft member 160 by pushing the proximal rim 184 b of the drive collar 184 proximally with the movable handle 122 (FIG. 10) as indicated by arrow D4 (FIG. 11). A spring 189 is constrained between a proximal facing surface of the drive collar 184 and a proximal spring stop 115. The proximal spring stop 115 engages the opposing proximal locking slots 171 a, 171 b (FIG. 3A) extending through the proximal portion 166 (FIG. 3A) of the outer shaft member 160 to couple the proximal spring stop 115 to the outer shaft member 160. Thus, the proximal spring stop 115 serves as a proximal stop against which spring 189 compresses.

Distal longitudinal motion is imparted to the outer shaft member 160 by driving the drive collar 184 distally with the movable handle 122 as indicated by arrow D3 (FIG. 10). Distal longitudinal motion of the drive collar 184 induces a corresponding distal motion of the outer shaft member 160 by virtue of the coupling of the drive collar 184 to opposing distal locking slots 181 a, 181 b extending through the proximal portion 166 of the outer shaft member 160 (FIG. 3A).

Proximal longitudinal motion of the outer shaft member 160 draws jaw member 132 proximally such that the cam pin 192 advances distally to pivot jaw member 130 toward jaw member 132 to move the end effector 114 to the closed configuration as described above with reference to FIG. 6. Once the jaw members 130 and 132 are closed, the outer shaft member 160 essentially bottoms out (i.e., further proximal movement of the outer shaft member 160 is prohibited since the jaw members 130, 132 contact one another). Further proximal movement of the movable handle 122 (FIG. 10), however, will continue to move the drive collar 184 proximally. This continued proximal movement of the drive collar 184 further compresses the spring 189 to impart additional force to the outer shaft member 160, which results in additional closure force applied to tissue grasped between the jaw members 130, 132 (see FIG. 2B).

Referring again to FIG. 10, the trigger 126 is pivotally supported in the housing 112 about a pivot boss 103 protruding from the trigger 126. The trigger 126 is operatively coupled to the knife rod 102 by a knife connection mechanism 104 such that pivotal motion of the trigger 126 induces longitudinal motion of the knife rod 102. The knife connection mechanism 104 includes upper flanges 126 a, 126 b of the trigger 126 and a knife collar 110.

Referring now to FIGS. 11, 12A, and 12B, the knife collar 110 includes a pair of integrally formed pin bosses 139 a, 139 b extending from opposing sides thereof. As shown by FIG. 12B, the knife collar 110 includes an interior circular channel 113 that captures the angled proximal end 108 of the knife rod 102 to couple the knife rod 102 to the knife collar 110. Upon longitudinal motion of the outer shaft member 160, the angled proximal end 108 of the knife rod 102 translates longitudinally within the knife slot 168 (FIG. 3A) of the outer shaft member 160 such that the longitudinal motion of outer shaft member 160 is unimpeded by the angled proximal end 108 of the knife rod 102. Upon rotation of the elongated shaft 116 and end effector 114 about the longitudinal axis A-A via the rotation knob 128 (FIG. 1), the angled proximal end 108 of the knife rod 102 freely rotates within the interior circular channel 113 of the knife collar 110 such that the outer and inner actuation members 160 and 180 (removed from view in FIG. 12B for clarity), and the knife rod 102 rotate within the knife collar 110 about the longitudinal axis A-A. In this way, the knife collar 110 serves as a stationary reference for the rotational movement of the outer shaft member 160, the inner actuation member 180, and the knife rod 102.

Referring again to FIG. 10, the upper flanges 126 a, 126 b of the trigger 126 include respective slots 127 a, 127 b defined therethrough that are configured to receive the pin bosses 139 a, 139 b, respectively, of the knife collar 110 such that pivotal motion of the trigger 126 induces longitudinal motion of the knife collar 110 and, thus, the knife rod 102 by virtue of the coupling of knife rod 102 to the knife collar 110.

Referring now to FIGS. 11 and 12A, when the trigger 126 is moved to induce motion of the knife collar 110 in order to translate the blade 156 through the knife channel 158, the knife collar 110 translates along the outer shaft member 160 in the direction of arrow A5 to abut a spring 119 such that spring 119 compresses against an interior portion of the rotation knob 128 (FIG. 10). The spring 119 biases the knife collar 110 proximally along the outer shaft member 160.

As indicated above with respect to the embodiment depicted in FIG. 10, the forceps 100 may include an enhanced switch control feature configured to prevent the deactivation and reactivation of the switch 136 to terminate and reinitiate, respectively, the delivery of electrosurgical energy to the end effector 114 during operation of the trigger 126. With reference to FIGS. 13A, 13B, 13C, and 13D, another such embodiment is depicted, wherein a spring lever 135 (e.g., leaf spring) extends from a proximal side of the moveable handle 122 and includes an activation post 135 a configured to engage and depress the button 137 upon approximation of the moveable handle 122 with the stationary handle 120 (FIG. 13C). The spring lever 135 is biased away from the surface of the moveable handle 122 from which it extends such that upon approximation of the moveable handle 122 with the stationary handle 120, the button activation post 135 a engages and depresses the button 137 and a spring force is applied on the button 137 by the spring lever 135. Upon further approximation of the moveable handle 122 with the stationary handle 120, the button activation post 138 engages the spring lever 135 to cause the activation post 135 a to apply additional force on the button 137. If the moveable handle 122 inadvertently moves distally away from the stationary handle 120 (e.g., during operation of the trigger 126), as depicted by arrow M7 in FIG. 13D, the spring lever 135 serves to mitigate the effects of this distal movement of the moveable handle 122 by maintaining a spring force on the button 137. This spring force maintained on the button 137 is sufficient to keep the switch 136 activated during at least a portion of travel of the moveable handle 122 in the distal direction (arrow M7), such that the switch 136 is not deactivated and reactivated during operation of the trigger 126. As the moveable handle 122 moves farther away from the stationary handle 120 to move the end effector 114 to the open configuration (FIG. 13A), the spring force maintained on the button 137 by the spring lever 135 relents and, as a result, the switch 136 is deactivated.

Referring again to FIGS. 13A, 13B, 13C and 13D, a sequence of motions may be initiated by moving the movable handle 122 to induce motion of the outer shaft member 160 in order to close the jaws 130, 132, and by moving the trigger 126 to induce motion of the knife collar 110 in order to translate the blade 156 through the knife channel 158. Initially, both the moveable handle 122 and the knife trigger 126 are in a distal or un-actuated position as depicted in FIG. 13A. This arrangement of the moveable handle 122 and trigger 126 sustains the end effector 114 in the open configuration (FIG. 2A) wherein the jaw members 130, 132 are substantially spaced from one another, and the knife blade 156 is in a retracted or proximal position with respect to the jaw members 130, 132. When both the moveable handle 122 and the knife trigger 126 are in the distal, un-actuated position, pivotal motion of the knife trigger 126 in a proximal direction, i.e., toward the stationary handle 120, is prohibited by interference between the trigger 126 and moveable handle 122. This interference prohibits advancement of the knife blade 156 through the knife channel 158 when the end effector 114 is in the open configuration.

The movable handle 122 may be moved from the distal position of FIG. 13A to an intermediate position depicted in FIG. 13B to move the jaw members 130, 132 to the closed configuration (FIG. 2B). As the movable handle 122 pivots in the direction of arrow M1 (FIG. 13B), the drive surface 197 b of the movable handle 122 engages the proximal rim 184 b of the drive collar 184. The drive collar 184 is driven proximally such that the spring 189 proximally biases the proximal spring stop 115 and, thus, the outer shaft member 160 is driven proximally in the direction of arrow M2 (FIG. 13B). As discussed above with reference to FIG. 6, proximal movement of the outer shaft member 160 serves to advance the cam pin 192 distally though the cam slots 130 c, 132 c (FIG. 3A) of the jaw members 130, 132, respectively, and thus pivot jaw member 130 toward jaw member 132 (FIG. 2B). As the jaw members 130, 132 engage one another and no further pivotal movement of the jaw members 130, 132 may be achieved, further distal movement of the cam pin 192 and further proximal movement of the outer shaft member 160 are prevented.

As the movable handle 122 is moved from the distal position of FIG. 13A to the intermediate position depicted in FIG. 13B, a tooth 122 a extending proximally from an upper portion of the moveable handle 122 engages a clicker tab 120 a supported within the stationary handle 120 to generate a tactile and/or audible response. This response generated by the clicker tab 120 a corresponds to a complete grasping of tissue between the jaw members 130, 132 and serves to indicate to the surgeon that further proximal actuation of the moveable handle 122 will cause the button activation post 135 a to engage the depressible button 137. As the moveable handle 122 is moved from the intermediate position of FIG. 13B to the actuated or proximal position of FIG. 13C, the tooth 122 a is positioned proximally of the clicker tab 120 a and the button activation post 135 a depresses the depressible button 137, thereby activating the switch 136 disposed within the stationary handle 120 to initiate the delivery of electrosurgical energy to the end effector 114 to generate a tissue seal or otherwise treat tissue.

As the movable handle 122 is moved from the intermediate position of FIG. 13B to the actuated or proximal position of FIG. 13C, the pressure applied by the jaw members 130, 132 is increased. As the movable handle 122 pivots further in the direction of arrow M3 (FIG. 13C), the drive surface 197 b presses the proximal rim 184 b of the drive collar 184 further proximally against the spring 189 in the direction of arrow M4 (FIG. 13C). The spring 189 is compressed against the proximal spring stop 115, and a tensile force is transmitted through the outer shaft member 160 to the jaw members 130, 132. The tensile force supplied by the spring 189 ensures that the jaw members 130, 132 apply an appropriate pressure to effect a tissue seal.

When the movable handle 122 is in the actuated or proximal position, the knife trigger 126 may be selectively moved from the distal position of FIG. 13C to the proximal position of FIG. 13D to advance the knife blade 156 distally through knife channel 158. The knife trigger 126 may be pivoted in the direction of arrow M5 (FIG. 13D), about pivot boss 103 to advance the flanges 126 a, 126 b of the knife trigger 126 distally in the direction of arrow M6 such that the pin boss 139 b translates within slot 127 b from the position shown in FIGS. 13A-13C to the position shown in FIG. 13D. Although not explicitly shown in FIGS. 13A-13D, pin boss 139 a translates within slot 127 a in the same manner as described above with respect to pin boss 139 b and slot 127 b. Movement of flanges 126 a, 126 b draws the knife collar 110 distally, which induces distal longitudinal motion of the knife rod 102 by virtue of the coupling of the knife rod 102 to the knife collar 110, as described above with reference to FIG. 12B.

While several embodiments of the disclosure have been shown in the drawings, it is not intended that the disclosure be limited thereto, as it is intended that the disclosure be as broad in scope as the art will allow and that the specification be read likewise. Therefore, the above description should not be construed as limiting, but merely as examples of particular embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.

Although the foregoing disclosure has been described in some detail by way of illustration and example, for purposes of clarity or understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the appended claims. 

What is claimed is:
 1. An electrosurgical instrument, comprising: a housing; an elongated shaft extending from the housing; a pair of opposing jaw members disposed at a distal portion of the elongated shaft and configured to connect to a source of electrosurgical energy, at least one of the jaw members movable relative to the other jaw member between an open position and a closed position; a movable handle operably coupled to the housing and configured to move between an unactuated position and an actuated position to move at least one of the jaw members between the open and closed positions; a switch supported by the housing and configured to move between an activated position and a deactivated position to control delivery of electrosurgical energy to the jaw members; a depressible button having a proximal portion coupled to the switch and a distal portion extending from the housing, the distal portion of the depressible button configured to be engaged by the movable handle to move the switch between the activated and deactivated positions; a switch activation post housed within the depressible button, the switch activation post extending from the distal portion of the depressible button and configured to engage the switch to move the switch to the activated position upon depression of the depressible button; and a coiled spring disposed around the switch activation post and housed within the depressible button, the coiled spring configured to maintain a spring force on the switch to maintain the switch in the activated position during at least a portion of travel of the moveable handle toward the unactuated position.
 2. The electrosurgical instrument according to claim 1, wherein the movable handle includes an upper portion disposed within the housing and a lower portion disposed exterior to the housing, the lower portion of the movable handle configured to engage the depressible button upon movement of the movable handle to the actuated position.
 3. The electrosurgical instrument according to claim 1, wherein the movable handle is configured to move in a distal direction to the unactuated position.
 4. The electrosurgical instrument according to claim 1, wherein the movable handle is configured to move in a proximal direction to the actuated position.
 5. The electrosurgical instrument according to claim 1, further comprising a button activation post extending from a proximal side of the movable handle and configured to engage the depressible button upon movement of the movable handle to the actuated position.
 6. The electrosurgical instrument according to claim 1, wherein movement of the movable handle moves the elongated shaft longitudinally relative to a stationary actuation member axially disposed within the elongated shaft to move at least one of the jaw members between the open and closed positions, the stationary actuation member including a cam pin configured to engage a camming slot included on at least one of the jaw members to move at least one of the jaw members between the open and closed positions upon movement of the movable handle.
 7. The electrosurgical instrument according to claim 1, wherein the switch activation post is configured to disengage the switch during the at least a portion of travel of the moveable handle toward the unactuated position.
 8. An electrosurgical instrument, comprising: a housing; an elongated shaft extending from the housing; a pair of opposing jaw members disposed at a distal portion of the elongated shaft and configured to connect to a source of electrosurgical energy, at least one of the jaw members movable relative to the other jaw member between an open position and a closed position; a movable handle operably coupled to the housing and configured to move between an unactuated position and an actuated position to move at least one of the jaw members between the open and closed positions; a switch supported by the housing and configured to move between an activated position and a deactivated position to control delivery of electrosurgical energy to the jaw members; a depressible button coupled to the switch and extending from the housing, the depressible button configured to be engaged by the movable handle to move the switch between the activated and deactivated positions; a switch activation post housed within the depressible button, the switch activation post configured to engage the switch to move the switch to the activated position upon movement of the movable handle to the actuated position; and a biasing member housed within the depressible button and configured to maintain the switch in the activated position during at least a portion of travel of the moveable handle toward the unactuated position.
 9. The electrosurgical instrument according to claim 8, wherein the biasing member is a coiled spring disposed around the switch activation post.
 10. The electrosurgical instrument according to claim 8, wherein the movable handle includes an upper portion disposed within the housing and a lower portion disposed exterior to the housing, the lower portion of the movable handle configured to engage the depressible button upon movement of the movable handle to the actuated position.
 11. The electrosurgical instrument according to claim 10, further comprising a button activation post extending from a proximal side of the lower portion of the movable handle and configured to engage the depressible button upon movement of the movable handle to the actuated position.
 12. The electrosurgical instrument according to claim 8, wherein the movable handle is configured to move in a distal direction to the unactuated position and in a proximal direction to the actuated position.
 13. The electrosurgical instrument according to claim 8, wherein movement of the movable handle moves the elongated shaft longitudinally relative to a stationary actuation member axially disposed within the elongated shaft to move at least one of the jaw members between the open and closed positions, the stationary actuation member including a cam pin configured to engage a camming slot included on at least one of the jaw members to move at least one of the jaw members between the open and closed positions upon movement of the movable handle.
 14. The electrosurgical instrument according to claim 8, wherein the switch activation post is configured to disengage the switch during the at least a portion of travel of the moveable handle toward the unactuated position.
 15. A method of controlling activation of a switch of an electrosurgical instrument for controlling delivery of electrosurgical energy to tissue, comprising: moving a movable handle relative to a housing from an unactuated position to an actuated position to move a pair of opposing jaw members from an open position to a closed position to grasp tissue between the jaw members; engaging a depressible button extending from the housing with the movable handle upon movement of the movable handle to the actuated position to move a switch operably coupled to the depressible button from a deactivated position to an activated position to deliver electrosurgical energy to tissue grasped between the jaw members; moving the movable handle from the actuated position toward the unactuated position; and maintaining a force on the switch to maintain the switch in the activated position during at least a portion of the movement of the movable handle from the actuated position toward the unactuated position.
 16. The method according to claim 15, wherein maintaining the force on the switch includes moving a spring disposed within the depressible button from a compressed configuration toward a decompressed configuration.
 17. The method according to claim 15, wherein engaging the depressible button extending from the housing with the movable handle includes causing a switch activation post disposed within the depressible button to engage the switch and move the switch to the activated position.
 18. The method according to claim 15, wherein moving the movable handle relative to the housing includes moving the movable handle in a proximal direction to the actuated position.
 19. The method according to claim 15, wherein moving the movable handle relative to the housing includes moving the movable handle in a distal direction to the unactuated position.
 20. The method according to claim 15, wherein engaging the depressible button extending from the housing with the movable handle includes engaging the depressible button with a portion of the movable handle that is disposed exterior to the housing. 